Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

Standards Of Care – Ventricular Tachycardia

 

Is it possible to write protocols that are based on good evidence, rather than on GOBSAT (Good Old Boys Sitting Around a Table) rules?
 

The Standard Of Care is what the popular kids are doing because of peer pressure, a lack of understanding of the available evidence, and a fear of law suits.

Peer pressure?

If we don’t do what everyone else is doing, we will harm patients?

Patient care is not a popularity contest, otherwise there would be no need for doctors. A majority of neighbors could come up with the Standard Of Care.

Is there any reason to discourage doctors from challenging the Standard Of Care?

Well . . . .

What will everyone hide behind, if we admit that the Standard Of Care may not be the best available care?

What will everyone hide behind, if we admit that the Standard Of Care may be bad care?

If we admit that, will memorization and application of a bunch of Standards Of Care be good for patients?
 

What about V Tach (Ventricular Tavhycardia)? The AHA (American Heart Association) writes guidelines for treatment, which are generally accepted as Standards Of Care and copied into EMS protocols. To the credit of the AHA, they do continually review the available evidence and revise their guidelines.
 


 

Many devotees of Standards Of Care whine about these changes. How can we be expected to provide care that doesn’t get us in trouble, if the definition of what doesn’t get us in trouble is constantly changing? It is as if we will be expected to understand what we are doing, rather than to just be expected to memorize and apply the Standards Of Care. It is as if we are expected to continue learning because we don’t know everything.

Amiodarone may be the ultimate standard Standard Of Care.

A Fib (Atrial Fibrillation)?

Give amiodarone.

A Flutter (Atrial Flutter)?

Give amiodarone.

V Tach?

Give amiodarone.

Wide complex tachycardia that could be anything?

Give amiodarone.

V Fib (Ventricular Fibrillation)?

Give amiodarone.

Sinus tachycardia (due to sepsis, or hemorrhage, or pain, or epinephrine, or dehydration, or anxiety, or fever, or . . . )?

Some people will still give amiodarone.

Why?

It’s the Standard Of Care. This is the excuse for not being competent. Just memorize some Standards Of Care, sprinkle them around liberally, and everything will be OK – but never, ever question the Standard Of Care.

This is no different from the protocol monkey, who is faced with the multiple choice protocol decision.

Tachycardia problem?

Tachycardia treatment.

Amiodarone vs. adenosine. Tough choice. Narrow = adenosine. Wide = amiodarone.

But does amiodarone do a good job of treating emergency patients?

Different studies show that amiodarone is only 29% effective at terminating V Tach,[1] only 25% effective at terminating V Tach, [2], and only 15% effective at terminating V Tach within 20 minutes, but if we don’t mind waiting an hour it can be as much as 29% effective.[3]

What else is available?

In the 2010 ACLS guidelines, procainamide is listed as Class IIa, LOE B, while amiodarone is only Class IIb, LOE B.

What does that mean?
 

Class IIa
Benefit >> Risk
It is reasonable to perform procedure/administer treatment or perform diagnostic test/ assessment.

Class IIb
Benefit Risk
Procedure/treatment or diagnostic test/assessment may be considered.[4]

 

There is much better evidence that procainamide is effective.
 

Procainamide and sotalol should be avoided in patients with prolonged QT.[5]

 

But that is a mistake.

Amiodarone is a potent QT segment prolonging drug.
 

Proarrhythmia
Like all antiarrhythmic agents, amiodarone I.V. may cause a worsening of existing arrhythmias or precipitate a new arrhythmia. Proarrhythmia, primarily torsades de pointes (TdP), has been associated with prolongation by amiodarone I.V. of the QTc interval to 500 ms or greater. Although QTc prolongation occurred frequently in patients receiving amiodarone I.V., torsades de pointes or new-onset VF occurred infrequently (less than 2%). Patients should be monitored for QTc prolongation during infusion with amiodarone I.V. Combination of amiodarone with other antiarrhythmic therapy that prolongs the QTc should be reserved for patients with life-threatening ventricular arrhythmias who are incompletely responsive to a single agent.
[6]

 

If the only advantage of amiodarone over procainamide is QT prolongation, but that advantage is not real, why should we prefer amiodarone to procainamide?

Footnotes:

[1] Amiodarone is poorly effective for the acute termination of ventricular tachycardia.
Marill KA, deSouza IS, Nishijima DK, Stair TO, Setnik GS, Ruskin JN.
Ann Emerg Med. 2006 Mar;47(3):217-24. Epub 2005 Nov 21.
PMID: 16492484 [PubMed – indexed for MEDLINE]

[2] Amiodarone or procainamide for the termination of sustained stable ventricular tachycardia: an historical multicenter comparison.
Marill KA, deSouza IS, Nishijima DK, Senecal EL, Setnik GS, Stair TO, Ruskin JN, Ellinor PT.
Acad Emerg Med. 2010 Mar;17(3):297-306.
PMID: 20370763 [PubMed – indexed for MEDLINE]

Free Full Text from Academic Emergency Medicine.

[3] Intravenous amiodarone for the pharmacological termination of haemodynamically-tolerated sustained ventricular tachycardia: is bolus dose amiodarone an appropriate first-line treatment?
Tomlinson DR, Cherian P, Betts TR, Bashir Y.
Emerg Med J. 2008 Jan;25(1):15-8.
PMID: 18156531 [PubMed – indexed for MEDLINE]

[4] Table 3. Applying Classification of Recommendations and Level of Evidence
2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
Part 1: Introduction
Table 3

I have modified this table solely for the purpose of clarity of presentation, by modifying color and font. None of the words have been changed.

[5] Wide-Complex Tachycardia
2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
Part 8: Adult Advanced Cardiovascular Life Support
Part 8.3: Management of Symptomatic Bradycardia and Tachycardia
Tachycardia
Free Full Text from Circulation

[6] AMIODARONE HYDROCHLORIDE injection, solution
[Bedford Laboratories]

DailyMed
Warnings
FDA Label

.

Speak Your Mind